1. Field of the Invention
This invention generally relates to a heat sink for a computer system, and more particularly to a heat sink system for a computer wherein the heat sink attaches to the computer system enclosure.
2. Description of the Related Art
Computer systems such as personal computers, workstations, and portable computers, typically include components housed within an enclosure. Some components, such as central processing units (CPUs) and memory chips, typically mount on circuit boards within the enclosure. Other components, such as circuit boards and disk drives, typically mount to a chassis of the computer system.
Some computer components, such as CPUs, generate heat during use. A component can only function properly when the temperature of the component is at or below a maximum operating temperature. Often, the package of a component is too small to allow enough heat transfer from the package to keep the component at or below the maximum operating temperature using only natural convection. Such components require additional cooling. If the temperature of a computer component exceeds the maximum operating temperature of the component, or if the temperature within the computer enclosure exceeds a maximum operating temperature, a reduction of computer performance may occur. Eventually, the components of the computer system can be permanently damaged or destroyed if the computer components or the computer system operate at too hot a temperature.
Trends in the computer industry include producing faster and smaller computer systems. Fast computer processors have been produced, but the amount of heat generated during use by the fast processors has also increased. Combining computer components that generate heat into a small computer system enclosure leads to problems of removing the heat from the computer components and from the computer system enclosure.
A fan or fans may be used to provide forced convection cooling of a computer component or a computer system. Adding a fan to a computer system may not be desirable. Fans can be noisy, expensive, and a fan is often the shortest-lived component of a computer system. Having a fan in a computer system may lower the reliability of the entire computer system. If the fan fails, other system components may be permanently damaged or destroyed. In some systems, the addition of a fan or fans to provide component cooling may be a necessity. In other systems, the use of heat sinks and natural convection may provide sufficient cooling.
One type of heat sink provides a thermal connection between a component being cooled and a large convection cooled surface area. Typically, such heat sinks mount directly to a component, to the component's socket on a circuit board, or to the circuit board. Practical size and weight limits exist for heat sinks that mount on the component, on the component socket, or on the circuit board. For example, a tall heat sink mounted directly on the component may not be practical. Jostling a tall heat sink mounted on a component may damage the connection between the component and the circuit board. Mishandling a tall heat sink mounted on the component may knock the heat sink off of the component. Socket and circuit board mounted heat sinks may greatly increase the assembly cost of a computer system.
Space limitations within a computer system enclosure may limit the size of heat sinks available for use in the computer system. If a heat sink is too large, it may overlap areas of the computer that require service access. Such areas include, but are not limited to EPROM, RAM modules, and test points.
A relatively inexpensive way of attaching a heat sink to a component is to purchase the computer device with the heat sink pre-attached to the device by the manufacturer. Typically, the device with the pre-attached heat sink is loaded onto a circuit board by automatic placement equipment. A disadvantage of buying a component with a pre-attached heat sink is that the component and heat sink combination might be too large to be handled by the automatic placement equipment.